Abstract: A radar sensor assembly that includes a radar sensor and a holder assembly is provided. The holder assembly includes a base plate, a first wall, a second wall, a third wall, and a bottom wall. Each of the first wall, the second wall, and the third wall extends from the base plate, and along with the bottom wall, define a sensor-holding portion. The first side and the second side define a sliding side to allow slidable accommodation of the radar sensor, in the sensor-holding portion. The sliding side includes a retention tab, which depresses to facilitate sliding of the radar sensor into the sensor-holding portion, and lifts to retain the radar sensor in the sensor-holding portion. At least one of the first wall, the second wall, and the third wall, includes one or more retention elements that prevent displacement of the radar sensor.